Design of a Four-Atom Cluster Embedded in Carbon Nitride for Electrocatalytic Generation of Multi-Carbon Products

The development of efficient and stable catalysts for the electrocatalytic CO₂ and CO reduction reactions (CORR) is under active investigation, but the problems of poor selectivity and low efficiency for C₂ products still exist. We design a two-dimensional carbon nitride material (C₅N₂H₂) that contains an eight N-atom structure capable of coordinating four-metal atom clusters and supporting simultaneously two carbon oxide molecules needed for the C₂ coupling. The designed material has excellent electrical conductivity and stability. After high-throughput screening of catalytic performance of multiple four-metal clusters embedded into the framework, we systematically investigate the CORR process of 11 candidates. We find that Cu₄-C₅N₂H₂ has superior selectivity and low limiting potential for generating ethylene, while Cu₂Zn₂-C₅N₂H₂ is selective and efficient to synthesize ethanol. Further, we discover a novel type of descriptor related to 2D material flexibility to evaluate the potential-determining step for generating ethylene. Our report both broadens the possibilities for few-atom CO reduction and demonstrates a novel substrate flexibility-related descriptor to predict the catalytic performance of materials.